High speed metal stamping presses are known which output many hundreds or thousands of pieces per hour which are stamped out from metal sheet stock being fed to the press, typically by an automatic coil feed system. Scrap material is then ejected from the press along with the stamped out parts.
More particularly, in the field of motor rotor and stator lamination stamping, it is known to employ progressive dies for stamping out motor laminations for rotors and stators. These motor laminations are typically formed roughly in the form of a circle or polygon with the stator lamination being larger than the rotor lamination for matching parts since the rotor fits within the inner aperture of the stator. The rotor also has an inner aperture.
In high speed lamination presses, it has previously been known to remove the stamped out parts in a manual manner wherein the parts fall through the bottom of the die and through a hole in the bolster plate beneath the die where they are accumulated in a stack. The bolster plate has a lower cutout portion where the stacked laminations can be removed such as by use of a simple metal hook manually operated to pull the stacks away from beneath the bolster plate, or by using a parts conveyor. The stacks are thereafter manually placed on a stacking skid by the person or persons employed in the removal and stacking of the laminations. If a desired number of laminations per stack is required, then the operator must manually measure the stack of laminations prior to placing the stacks on the shipping skid. A proper stack of laminations can be created by the press stroke counter.
A number of techniques have been developed to automate the manual method. In one such technique in the prior art, instead of the punched out laminations exiting vertically from the die they are carried through horizontally onto an output conveyor. Thereafter, a magnetic conveyor arranged overhead to the output conveyor conveys the laminations to a station which has a temporary parts accumulator above a mandrel. The laminations are accumulated on the mandrel such that a bottom plate of the mandrel lies between a conveyor formed of two parallel segments. As the mandrel and bottom plate are moved downwardly, the stacks come to rest on the parallel conveyor segments and can be conveyed away. While this is occurring, the temporary parts accumulator positioned directly beneath the magnetic conveyor formed by a stopper above the mandrel accumulates the parts until the mandrel can be repositioned to accumulate another group of parts.
Other even more complicated systems are employed in the prior art involving multiple conveyors and mandrels located on the turn table and temporary parts accumulation stations.
With such prior art methods, there are at least the following disadvantages:
1. They are expensive to manufacture;
2. They are slow;
3. Multiple conveyors are required;
4. Frequent jam-ups occur;
5. It is difficult for the operator to constantly check quality of the parts being removed from the press and stacked.
It is an object of the present invention to provide for an automatic parts handling system and method which is sufficiently fast and jam-up free so as to allow a substantial increase of the press speed, such as a doubling of the press speed.
It is a further object of the invention to provide ease of inspection of the parts so that it is easy to see bad parts before too many of them have accumulated in the stack.
It is a further object of the invention to have a system which can be easily modified to accommodate a variety of different inside and outside diameters of parts such as motor stators and motor rotors.
It is a further object of the invention to provide a system which is mobile.
It is another object of the invention to reduce the expense of manufacture.
It is a further object of the invention to provide a more reliable parts handling system which eliminates or greatly reduces jam-ups which can occur.
It is another object of the invention to provide a system which can be easily changed to accommodate either a stator or a rotor of a matching lamination set.
According to the method and apparatus of the invention, the parts handling device is provided for handling parts having a central aperture output from a press. A curved slide extends in sloping fashion with its upper end being positioned at the end of the parts conveyor press and its lower end at a location for unloading accumulated parts. A frame is provided having first, second, and third clamp assemblies mounted thereon. The support the tube, first, second and third clamping rings are provided beneath the curved surface of the slide at a spaced relationship from one another and in alignment with the clamp assemblies. The clamp assemblies clamp onto the first, second and third clamping rings. When at least two of the clamp assemblies are closed, the tube is fully supported in its sloped position. A control system is provided for opening and closing the first, second and third clamp assemblies in a sequence permitting the parts to accumulate in front of either the first, second or third clamping assemblies.
In a method of operation of the system, in a first step the first clamp mechanism is opened and the second and third clamp assemblies are closed so that parts accumulate in a stack in front of the second clamp assembly. In a second step, the first and third clamp assemblies are closed and the second clamp assembly is opened so that the stack now moves by gravity in front of the third clamp assembly. In a third step, the first and second clamp assemblies are closed and the third clamp assembly is opened so that the stack now moves to a position after the third clamp assembly where the operator can remove the stack. In a fourth step, the first clamp assembly is opened and the second and third clamp assemblies are closed which is the same operating condition as step 1. In a fifth step, the operator unloads the stack at the end of the tube while parts are again accumulating in front of the second clamp assembly.